Eye-popping Amphibians

Secretive and rarely seen, caecilians are small limbless amphibians that live underground in the tropics, feeding on worms and insects. One East African species, Scolecomorphus kirkii, was studied in captivity for the first time only this past year. S. kirkii turned out to have a trait unique among vertebrates: the pencil-size creature can pop its eyes--which are attached to small tentacles--out of its skull (shown at left).

Like most caecilians, says biologist James O’Reilly of Northern Arizona University, S. kirkii has extendable tentacles, thought to be chemical sensors, that lie in grooves on each side of the snout. Lidless caecilian eyes are usually separate from the tentacles and covered with skin. But S. kirkii‘s eyes are attached to the tentacles, which when fully extended carry each eye out from its skin sheath and beyond the head. These creatures seem to spend more time near the surface than most caecilians, says O’Reilly, so positioning the eyes to maximize their ability to detect light may be more important to them.